This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. TSG-6, the secreted product of tumor necrosis factor-stimulated gene-6, is composed of a Link module and a CUB module domain. The Link module is involved in binding to glycosaminoglycans and the entire system is in someway involved in remodeling the extracellular matrix. This is a process that normally occurs in response to injury of blood vessels but also occurs in rheumatoid arthritis and osteo-arthritis. The particular glycosaminoglycans to which the TSG-6 Link module binds include hyaluronan, heparan sulfate and chondroitin sulfate, but it appears that the binding sites might be different and interact allosterically. Professor Day has supplied the plasmid and expression advice on this glycosaminoglycan-binding protein. The Resource is providing the chondroitin sulfate oligomers and the NMR expertise to structurally define the binding mode. The project will use specialized orientational constraints developed in the Resource to facilitate structure determination.